Piezoelectric ceramic composition is used as a piezoelectric element in the making of actuators, ultrasonic sensors, ultrasonic transducers or the like. Since piezoelectric ceramic composition has an excellent piezoelectric property, lead zirconate titanate (PZT) or the like, containing a lead compound, has thus far been practically used. However, due to a concern that such said composition containing a lead compound may negatively affect the environment, a lead-free piezoelectric ceramic composition is now attracting attention and is being researched and developed. The alkaline niobate piezoelectric ceramic composition, as disclosed below in Patent Document 1, is such a piezoelectric ceramic composition free of a lead compound.
The piezoelectric ceramic composition, as disclosed in Patent Document 1, is described as the composition formula {Lix(K1-yNay)1-x}(Nb1-zSbz)O3 within each composition range of x, y and z, such as 0<x≦0.2, 0<y<1 and 0<z≦0.2.